Institutional Signals in Marine Policy Shape Tourists’ Pro-Environmental Intentions: Asymmetric Psychological Pathways and a Behaviorally Informed Governance Framework

Marine tourism embodies a sustainability paradox: high economic value coexists with ecological harm. Yet how macro-level policies shape pro-environmental intentions among transient, socially disembedded tourists remains unclear. Integrating institutional signaling theory with the Theory of Planned Behavior, we analyze survey data from 413 coastal visitors in China. The results reveal an asymmetric mediation pattern: marine policy influences intention primarily through behavioral attitudes and, to a lesser extent, subjective norms, while perceived behavioral control, though a direct predictor, does not mediate this relationship. This highlights a key boundary condition of TPB in low-embeddedness contexts, where institutional signals substitute for absent social ties by activating cognitive pathways. Practically, we propose a tiered governance pathway—attitude-focused messaging at digital touchpoints, normative feedback at entry points, and visible on-site infrastructure—to translate policy into observable actions, advancing both theory and practice in sustainable marine tourism.